The background of the invention will be set forth in two parts.
1. Field of the Invention
This invention relates to a liquid cleaner, and more particularly, to such cleaner mechanisms utilizing centrifugal force to separate particulate matter from the fluid host.
2. Description of the Prior Art
Under relatively low flow rate conditions, a conventional filter cartridge type filter system has proven to be adequate where a high degree of filtration is not required and where the amount of contamination is relatively low. However, higher flow rates and higher concentrations of contaminants quickly clog a conventional cartridge filter and also generally introduce an undesired amount of flow restriction into the system.
Over the years, several techniques have been developed which take advantage of a centrifuge type mechanism in order to increase the filter effectiveness and lessen the flow restriction aspects of cartridge filter systems. A typical one of such prior art systems includes a rotating centrifuge cage having a cartridge filter element fixedly disposed therein. The filter cartridge rotates with the cage and tends to trap particulate matter therein, while the purified liquid is drawn off at the top of the cage through appropriate openings adjacent the periphery of the cage.
Since the cartridge element must rotate at the same rate as the centrifuge cage, it must be constructed to withstand the forces exherted on it, and must be replaced relatively frequently since the capacity of such a configuration is extremely limited.
In accordance with another filter scheme, liquid to be filtered passes through a rotating screen. In order to remove contaminants from the screen which would otherwise eventually block the liquid flow therethrough, a small percentage of the filtered liquid is caused to reverse its flow direction and move back through the screen to remove contaminants therefrom and cause them to flow to a sump. Although using a centrifugal principal, filter efficiency is relatively low as compared to the previously described system.
These and other prior art mechanisms may be reviewed in the following patents discovered in a Patent and Trademark Office search:
U.s. pat. No. 2,129,751 -- A. A. Wells et al. PA1 U.s. pat. No. 2,733,855 -- M. M. McCoy PA1 U.s. pat. No. 2,750,107 -- D. More PA1 U.s. pat. No. 2,792,172 -- W. H. Tait PA1 U.s. pat. No. 3,400,827 -- F. A. Ziherl PA1 U.s. pat. No. 3,599,792 -- P. W. Stripp PA1 U.s. pat. No. 3,633,754 -- D. C. Marsh PA1 U.s. pat. No. 3,858,793 -- D. J. Dundrey